Supplies of drinking water for domestic civilian consumption, as well as those for deployed military forces, are vulnerable to being contaminated with potentially toxic chemicals, such as nerve agents, blood agents, and concentrations of herbicides and/or pesticides. All of these chemicals when present in sufficient amounts can be detrimental to the health of anyone who drinks the contaminated water. In order to reduce the chances that the population, whether civilian or military, will consume contaminated water, it is important to quickly detect toxic chemicals and other dangerous impurities at the primary source of the water, i.e., the reservoir, river or lake, before substantial amounts of the contaminated water can be distributed to the ultimate consumers.
It has been discovered that naturally occurring biosensors such as, for example, algae and cyanobacteria, which are present in all surface water exposed to sufficient sunlight, can be potentially useful biosensors. In general, algae is ubiquitous and can grow year round in most climactic conditions. In addition, algae can survive on low concentrations of nutrients and/or on nutrients that are in forms unsuitable for large multi-cellular organisms. Thus, algae can be an ideal biosensor since it's found in virtually all surface water sources and can survive and reproduce without significant human maintenance.
In general, it is known that there is a correlation between the photosynthetic activity of plants and measurable fluorescence induction spectrums of plants. Additionally, it is also known that a change in the fluorescence induction spectrum or pattern of a plant can represent a change in photosynthetic capability, which can be caused by the presence of toxic chemicals. Furthermore, as described above, all natural sources of water exposed to sufficient sunlight contain algae, which produce characteristic fluorescence induction patterns during normal photosynthetic activity.
Recently, there has been an increased awareness that surface water, such as rivers, lakes and the like, could potentially be the target of terrorist attacks. More specifically, the public accessibility of most surface water sources increases the possibility that a chemical and/or biochemical toxin could be released into the water supply without being immediately detected. Additionally, with the large quantity of pesticides and herbicides employed by modern society, it is possible that an unknown, accidental leak of a toxin could occur that could pose significant health risks. The large number of water sources, along with the relative size of the water sources, also makes continuous human monitoring and testing of surface water sources a cumbersome, expensive and potentially impossible task. The water monitoring industry, as well as the federal government, has searched for a simple biosensor that can be used to detect toxins present in water sources. Thus, it would be desirable to provide a water source monitoring system that could continuously monitor water sources and reduce the need for humans to travel to a particular water source site for testing and analysis of the water.